Acoustical treatment for upholstered structures



g 8, 1939- T. M. PRUDDVENQ 2,168,627

ACOUSTICAL TREATMENT FOR U PHOLSTERED STRUCTURES Filed 001:. 5, 1957 Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE llheodore M. Prudden, Hingham, Mass. Application October 5, 1937, Serial No. 167,377

2 Claims.

This invention relates to acoustic treatment of upholstered'structures, particularly for the seats and side walls of vehicle bodies. In my prior Patent No. 2,077,262, I disclosed a method of re- 5 ducing sound in vehicle bodies which includes the use of a head lining sheet stretched tautly over acoustic corrective material beneath the under surface of the roof. The sheet had erected fibres flocked thereon and the simplest way of attaching said fibres was to coat the entire face of the sheet with a continuous coating of light cement.

The application of the adhesive as a light continuous coating was practical for a head lining m structure where, as a result of the sheetbeing tautly mounted, the interstices of the sheet were opened up for the passage of sound therethrough. Such head lining structure, however, has certain definite limitations which preclude its use as a satisfactory sound absorbing structure for upholstered surfaces, such as the side walls and seats of a vehicle body.

These may best be understood from theiollowing analysis of the difierences in the problems presented by the two different types of installations.

Head lining is usually out of contact with a passengers body and hence is notsubject to marking, that is to say, the change in the surface appearance of the erected fibres due to their being moved out of parallelism with other fibres by pressure, whereas upholstered structures, such as seat and side wall materials are constantly subjected to marking pressures.

I Accordingly one feature of my present invention is the provision of a seat and side wall structure in which the evidences of marking will be greatly reduced. This I accomplish by providing a.surface of broken evenness of erected fibres.

Head lining is not subject to wear, whereas upholstered structures, such as seat and side wall materials are. Hence for seat and side wall materials a heavier adhesive is necessary for the attachment of the erected fibres inorder that hesive ,withoufiincreasing the sound resistanceof the sheet, This Iaccomplish by appiyingthe 66 heavier adhesive as an interrupted or non-conthey may better resist the tendency oi abrasive tinuous coating. As a result, the sheet has heavily coated areas and uncoated areas. The coated areas are closely spaced by the uncoated areas and these uncoated areas permit the ready passage of sound therethrough to the underlying 5 sound absorbing material for absorption thereby without the necessity of stretching the sheet sotautly as to open up its interstices for the passage ef the sound therethrough, as would be necessary were the sheet to be continuously coated with a heavy adhesive.

Head lining is tautly mounted to prevent sagging, whereas seat material is not, and cannot be tautly mounted because it must yield with the deformation of the springs due to the weight of a passenger. The application of a heavier adhesive as a continuous coating to seat or side wall material, however, would stiffen the material to such a degree that it might crease permanently when deformed. Moreover, the material would be of such board-like character as not to lend itself readily to pleating or other upholstery needs.

Accordingly, a still further feature of my present invention is that the application of the adhesive as an interrupted or non-continuous coating gives the material the requisite limpness for use as a seat covering despite the fact that both the material and the adhesive are relatively heavier than those used in a head lining. In fact, with a head lining there is no occasion for having a thick, boardy application of the adhesive, even if such a boardy application were not detrimental if used, because pleatability is not a requirement in a head lining.

Other diilerences and advantages of my present structure will be evident from the accompanying specification and drawing wherein I describe and illustrate a preferred embodiment of my invention. I iii In the drawing:

Figs. 1 and 2 are fragmentary sections showing a vehicle door and seat, respectively, acoustically treated in accordance with my invention. Fig." 3 is a fragmentary perspective on an en- 'iarged scale of my sound absorbing structure, and

Fig. 4 is a section thereof. 7

In Fig. 1 I have indicated generally at I! a conventional doorstructure having'the' usual in.-

side panel of fibreboard or-the like ll.

In Fig. 2 I have indicated generally at i2 a 1 conventional seat structure.

My novel sound absorbing structure comprises a oi sound absorbing material ll of any suitable character applied to the upholstered structure, such as a door, seat or side wall, and a wear-resistant trim or covering consisting of a relatively heavy but flexible backing sheet H in surface contact with said sound absorbing material and having erected fibres l5 flocked on and cemented to its exposed face in a number of closely spaced tuft-like groups.

It is within the purview of my invention, however, to interpose a spacing sheet or its equivalent between the sound absorbing material i3 and the sheet I4, and accordingly the expression surface contact" as used herein is in its broader sense to connote either direct or indirect surface contact between the parts l3 and- I apply the cement as a relatively heavy interrupted or non-continuous coating, preferably in the form of a number of closely spaced dots, spots, stripes or the like It, the intervening uncoated areas I! of the sheet permitting relatively little obstruction to passage of sound therethrough to the underlying material l3 for absorption thereby.

I have made acoustic tests of my flocked covering in comparison with a woven pile fabric, both materials overlying the same sound absorber. These tests show that the high resistance to sound of the woven pile fabric prevents the underlying absorber from functioning as well as it does under my more open construction. In other words, greater sound absorption was achieved when my flocked material was the outer covering than when the woven pil'e fabric was used, although the woven pile fabric was of itself a somewhat better sound absorber than my flocked material.

When flocked on the sheet, the fibres l5 are'attached thereto only at the coated areas l6 (see Figs. 3 and 4) producing a surface of broken evenness of erected fibres which not only reduces sound reflection but also reduces the evidences of marking when the fibres are deflected by pressure of a body.

The area and spacement of the coated and uncoated portions of the backing sheet relative to each other may be varied as desired to give corduroy, wale or other efl'ects.

The sheet ll may be of any suitable material,

as cotton for example, which is permeable to sound and at the same time has sufilcient strength to resist the tearing strains to which it is subjected in service.

The flocked fibres may likewise be of any suitable character. these fibres may be of inorganic material, such as glass.

The sound absorbing material I! may also be For fireproof characteristicsof any desired character, as cotton wadding, or in the case of a seat, porous or sponge rubber.

The flocked sheet is less expensive than the conventional wools or worsteds' or the more expensive pile fabrics, such as mohair and velvet generally used asseat or side wall coverings, while comparing favorably with them in point of appearance and serviceability. It has the appearance of substantial density, yet when held up to the light, its openness and consequent permeability to sound is readily apparent. Certain manufacturing defects, 'such as imots in the sheet, or omission of a group of tuft-like fibres is made less evident by the broken evenness of the surface of the erected fibres, as is also the presence of specks of dirt or other foreign matter in the sheet, or variations in the length of the flocked fibres.

To further reduce evidences of marking, I may use a mixture of colors in the erected fibres. The flocking processlends itself to this mixture of colors, since all that is necessary, as contrasted with a woven pile fabric, to achieve this result is to mix the proper amount of each color in the bulk fibre before applying. The result of this mixtureof colors causes further unevenness of the surface appearance, so that the eye is not so readily attracted to the deflection (marking) of the fibres at some spot.

While I have discussed my invention with particular reference to the acoustic treatment of the side wall and seat. of a vehicle body, in which use it finds a field of immediate demand, the principles may be embodied in various types of upholstered structures.

What I therefore claim by Letters Patent is:

1. In combination, an interior surface carrying a porous sound absorbent material, and a sound penetrable and sound-reflection-reducing decorative and wear-resisting covering for said sound absorbent material, said covering comprising a limp flexible backing sheet in juxtaposition thereto, said sheet having interstices for the passage of air-home sound therethrough, having spaced applications of cement on its exposed face, and having erected fibres flocked on and attached to said exposed face by said cement, the spaces between said cement applications permitting air-borne sound to readily pass through the sheet and reach the underlying sound absorbent material.

2. The combination of claim 1, the spaces being both longitudinally and transversely of the sheet.

and desire to secure THEODORE M. PRU'DDEN. 

